Electric current rectifier



Oct. 13, 1931. 5, RUBEN 1,826,955

ELECTRIC CURRENT RECTIFIER Filed March 30. 1927 IN V EN TOR.

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Patented Oct. 13, 1931 UNITED STATES PATENT OFFQCE SAMUEL BUIBEN, OF NEWYORK, N. Y., ASSIGNOR TO RUBEN RECZLIFIEB CORPORATION, OF ENGLEWOOD, NEWJERSEY, A CORPORATION OF DELAWARE ELECTRIC CURRENT RECTIFIER Applicationfiled March 30, 1927. Serial No. 179,478.

This invention relates to electric current rectifiers and the like,which employ asymmetric couples of the dry surface-contact varietRictifiers of this variety are known, which are characterized by the useof a body of relatively electropos'itive material, employed as oneelectrode element, disposed in electrical contact with a body ofrelatively electronegative material employed as the other electrodeelement; there being an intervening film having inverse current-blockingproperties. Such rectifiers depend for their eration upon the resistanceand currentlocking characteristics of the film which forms as the resultof electrochemical action. Rectifiers depending on these characteristicsknown to the priorart, have been low in elliciency and limited in theirapplication to small currents, because of improper conditions forfilm-formation and maintenance, and become substantially inoperativeafter short periods of use.

The invention has for its object generally to provide an improved deviceof the character specified, which is eflicient, economical and readilymanufactured,and has a relatively long operating life for highcurrent-densities. To this end the electronegative electrode materialhere employed is preferably in powder form and selected to Withstand theeffects of electrolytic action.

A more specific object of the invention is to provide an asymmetriccouple in which the electronegative electrode element has relativelyhigh density and is also relatively conformable to the co-operatingsurface of the electropositive electrode element, so that there issubstantially a maximum area at all times at the contacting surfaces ofthe electrode elements.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the features of construction,combinations of elements, and arrangement of parts, which will beexemplified in the constructions hereinafter set forth and the scope ofthe application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings, in which:

Figure 1 shows diagrammatically a rectifying device constructed inaccordance with the invention;

Fig. 2 is a cross-sectional view showin th arrangement of the electrodeelements ere em loyed;

ig. 3 is an elevational view showing the form of the plate membersemployed in the asymmetric couple shown in Fig. 2; and

Fig. 4 is an elevational view showing a single asymmetric couple of thepresent invention mounted upon standards.

Referring now to the drawings and particularly to Fig. 2, 10 denotes acup, or receptacle having upturned sides, which is made of suitableconducting material; for example, copper, brass or steel, in which isdisposed a layer of material 11, here employed as the electronegativeelectrode element.

An electropositive electrode element is shown as a plate member, or disc12, of suitable material disposed in co-operative contact above thelayer of material 11. A second disc 13, adapted to serve as a backing,is disposed on the disc 12 and is here shown by double hatching. Anysoft metal which will absorb vibration and compensate for excessiveexpansion-contraction of the elements, may be chosen as the componentmaterial for disc 13, for example, lead. Above the disc 13 is a thirddisc 14 designed as a closure for the cup 10 and is preferably of thesame material as the cup 10.

When the asymmetric couples of the present invention are to be assembledby means of a bolt, the discs and cup 10 are perforated and have aninsulating tube 15 passed therethrough. In order also that theelectrical relation of the elements of the couple be not disturbed atthe outer edge, an insulating collar .16 is inserted between theupstanding rim of to build up a rectifying device of any convenientcharacter; for example, as a four-couple device as shown in Fi". l, oras a single-couple device, as shown in big. 4. In the latter a couple ais shown as disposed between conducting end-plates 17, formed to serveas standards.

In the device, illustrated in Fig. 1, two groups comprising two coupleseach, the coupies being disposed between conducting endplates 17 areinverted with respect to each other, and disposed in conducting relationwith the central terminal-plate 18. The clamping-bolt 19 extends throughthe assembled couples and has spring-washers 20 inserted between theterminal-plates 17 and the head-ends of the bolt. By the arrangementshown, it s seen that the four couples here employed comprise the armsof a Wheatstone bridge, of which the terminals provided at 18 and 21comprise one diagonal of the bridge circuit, and are adapted to serve asterminals for the output circuit of the rectifying device, here shown asconductors 22 and 23, leading to the terminals of a direct-currentconsuming device, here symbolically indicated by the signs and Theterminal-plates 17" disposed intermediately of the inverted groups arethe terminals of the other diagonal of the bridge clrcuit and serve asterminals for the alternating-current input circuit, here shown as theconductors 24 and 25, leading from the low tension side of a suitablestep-down transformer 26, which is here shown as connected to anoriginal source 27 of alternatingcurrent; for example, a commercialGO-cycle, 110-volt, AC-supply.

By the arrangement shown, when the conductor 24 has a plus polarity, theelectronegative electrode element in the cup 10 adjacent to theterminal-plate 17 to which the conductor 24 leads, will be positivelycharged and a direct current will pass, as a result of rectification, tothe plate 18, and thence by way of the conductor 22 to the plus terminalof the direct-current consuming device, and from thence by way ofconductor 23 and a second electronegative electrode element adjacent tothe terminal 21 to the conductor 25; and vice versa when the conductor25 has a plus polarity.

The electropositive electrode element here employed is a metallic bodyin solid form of substantially any relative stable but highly chemicallyactive electropositive element, for example, aluminum, boron, calcium,magnesium or zinc, such as taught in my co-pending application SerialNo. 69,215, filed November 16, 1925.

' The electronegative electrode element is a body preferably in powderedform, of a relatively highlv electronegative chemical element in arelatively pure state. In the ar rangement shown at 11, in Fig. 2, abody of powder which is relatively highly compressed, is disposed in thebottom of the cup 10. The chemical elements adapted to be components ofthe electronegative electrode elements are preferably the elements ofthe sixth group of chemical elements in the periodic table, which haverelatively high electrical conductivities and are adapted also to reactstrongly in forming an inverse current-blocking film at the contactingsurface between the electropositive and electronegative elements.Suitable chemical elements have been ascertained to be selenium andtellurium.

In order that there may be a sufficient ener gy for the reaction ofelectrochemically forming and maintaining the inverse currentblockingfilm supplied out of the resistance losses incident to the passage ofrectifying current through the asymmetric couple, as set forth in myco-pending applications Serial No. 38,781, filed June 20, 1925, andSerial No. 113,009, filed June 1, 1926, a resistance layer is providedat the contacting surface between the electropositive andelectronegative electrode elements. Such layer may be a thin coating ofan oxide 12 disposed over the contacting surface of the disc 12 and isplaced in contact with the electronegative element 11. Where the disc isof magnesium and the electronegative electrode element is powderedtellurium having an effective contacting surface of substantially onesquare inch, a uniform layer of .0001 of an inch in thickness of magnesium oxide on the magnesium disc is sufficient for the practice ofthe present invention. The pressure to be applied to the couple, as setforth in my application Serial No. 38,781, should be suiiicent toprevent the inverse current-blocking film for being .disrupted byelectrostatic repulsive forces operating at the contacting surfaces.

Where the electronegative electrode element is in powder form, it isadapted to adjust itself for intimate contact with the electropositiveelectrode element under substantially all conditions of operation andis. therefore. adapted for operation at substantially maximum currentdensities. It has been ascertained that in asymmetric couples of thischaracter in which the contacting surface has been electrolyticallyoxidized to provide a relatively rigid contacting resistance layer, acouple is produced capable of resisting the effects of the compositionby electrolysis, and in consequence has a high stability characteristicand is adapted for service under severe operating devices overrelatively long periods of time.

In a service, however. where compactness is more important than highcurrent density, an electronegative electrode element of the characterhere employed can still be made use of by casting the same into a soliddisc and assembling the rectifier, as taught in my copendin applicationSerial No. 750,939, filed Novem er18, 1924.

Since certain changes may be made in the above construction anddifferent embodiments of the invention could be made without departinfrom the scope thereof, it is intended that a l matter contained inthe'above description or shown in the accompanying drawing shall beinterpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim as new and desire to secureby Letters Patent, is:

1. In dry surface-contact rectifying devices and the like, an asymmetriccouple having an electronegative electrode element of metallictellurium, and an electropositive electrode element of a relative stablehighly chemically active electropositive metal formed to have a contactresistance adapted to supply the energy from resistance losses for theformation and maintenance of an inverse current-blocking film at thecontacting surface, and means for maintaining said cou ple assembledunder pressure sufficient for a relatively permanent rectifying effect.

2. In dry surface-contact rectifying de vices and the like, anasymmetric couple having an electronegative electrode element ofmetallic tellurium, and an electropositive electrode element of arelatively stable highly chemically active electropositive metal formedto have a contact resistance adapted to supply the energy fromresistance losses for the formation and maintenance of an inversecurrent-blocking film at the contacting surface, means in contact withsaid electropositive electrode element for absorbing the energy ofvibration in said couple, and means for maintaining said coupleassembled under pressure sufficient for a relatively permanentrectifying effect.

In dry surface-contact rectifying devices and the like, an asymmetriccouple having an electronegative electrode element of metallictellurium, and an electropositive electrode element of a solid body ofmetallic magnesium formed to have a resistance layer over its contactingsurface adapted to supply the energy from resistance losses for theformation and maintenance of an inverse current-blocking film at thecontacting surface, and means for maintaining said couple assembledunder pressure sufficient for a re I tively permanent rectifying effect.

4. In dry surface-contact rectifying devices and the like, an asymmetriccouple having an electronegative electrode element of metallictellurium, and an electropositive electrode element of a solid body ofmetallic magnesium formed to have a resistance layer of magnesium oxideuniformly disposed over its contacting surface adapted to supply theenergy from resistance losses for the formation and maintenance of aninverse currentblocking film at the contacting surface, means in contactwith said electropositive electrode element for absorbing the energy ofvibration in said couple, and means for maintaining said coupleassembled under pressure sufficient for a relativelypermanent-rectifying effect.

5. In dry surface-contact rectifying devices and the like, an asymmetriccouple having an electronegative electrode element of metallic telluriumin powder form, a conducttively stable highly chemically activeelectropositive metal disposed in said cup in contact with said powderelement and formed to have a contact resistance adapted to supply theenergy from resistance losses for the formation and maintenance of aninverse current-blocking film at the contact surface, and means formaintaining said couple assembled under pressure sufficient for arelatively permanent rectifying effect.

6. In dry surface-contact rectifying devices and the like, an asymmetriccouple having an electronegative electrode element of metallic telluriumin powder form, a conducting cup adapted to support the same, anc'lectropositive electrode in plate form of a relatively stable highlychemically active electropositive metal disposed in said cup in contactwith said powder element and formed to have a contact resistance adaptedto supply the energy from resistance losses for the formation andmaintenance of an inverse currenthlocking film at the contactingsurface; a second plate of soft metal disposed in said cup upon saidelectropositive electrode plate, and means for maintainin said coupleassembled under pressure su cient for a relatively permanent rectifyingeffect.

7. In dry surface-contact rectifying devices and the like, an asymmetriccouple having an electronegative electrode element of metallic telluriumin powder form; a conducting cup adapted to support the same, anelectropositive electrode in plate form of a relatively stable highlychemically active electropositive metal disposed in said cup in contactwith said powder element and formed to have a contact resistance adaptedto supply the energy from resistance losses for the formation andmaintenance of an inverse current-blocking film at the contactingsurface; a second plate of soft metal disposed in said cup upon saidelectropositive electrode plate; a third plate of conducting materialsimilar to said cup disposed upon said second plate and arranged toserve as a closure for said cup, and means for maintaining said coupleassembled under pressure sufficient for a relatively licrmanentrectifying effect.

8. In dry surfacecontact rectifying devices and the like. an asymmetriccouple having an clcctroncgutive electrode element of metallie telluriumin powder form; a conducting cup adapted to support the same; anelectropositive electrode element of a solid body of metallic magnesiumformed to have a resistance layer of magnesium oxide uniformly dispos'edover its contacting surface adapted to supply the energy from resistancelosses for the formation and maintenance of an inverse current-blockingfilm at the contacting surface;-a second plate of soft metal disposed insaid cup upon said electropositive electrode plate; a third plate ofconducting material similar to said cup, disposed upon said second plateand arranged to serve as a closure for said cup, and means formaintaining said couple assembled under pressure sufticient for arelatively permanent rectifying efi'ect.

9. A dry surface-contact rectifying device including an anode oftellurium and a cathode of a relatively highly electropositive metal.

10. A dry surface-contact rectifying device including an anode oftellurium and a cathode of magnesium.

11. A dry surface-contact rectifyin device comprising an anode oftellurium an a cathode of a relatively highly electropositive metal andan oxide layer therebetween.

12. A dry surface-contact rectifying device comprising an anode oftellurium and a cathode of magnesium and an oxide layer therebetween.

In testimony whereof I aflix my si nature.

SAMUEL RU EN.

lic tellurium in powder form; a conducting cup adapted to support thesame; an electropositive electrode e ement of a solid body of metallicmagnesium formed to have a resistance layer of magnesium oxide uniformlydispos'ed over its contacting surface adapted to supply the energy fromresistance losses for the formation and maintenance of an inversecurrent-blocking film at the contacting surface;-a second plate of softmetal disposed in said cup upon said electropositive electrode plate; athird plate of conducting material similar to said cup, disposed uponsaid second plate and arranged to serve as a closure for said cup, andmeans for maintaining said couple assembled under pressure sufficientfor a relatively permanent rectifying efl'ect.

9. A dry surface-contact rectifying device including an anode oftellurium and a cathode of a relatively highly electropositive metal.

10. A dry surface-contact rectifying device including an anode oftellurium and a cathode of magnesium.

11. A dry surface-contact rectifying device comprising an anode oftellurium and a cathode of a relatively highly electropositive metal andan oxide layer therebetween.

12. A dry surface-contact rectifying device comprising an anode oftellurium and a cathode of magnesium and an oxide layer therebetween.

In testimony whereof I aflix my signature.

SAMUEL RUBEN.

CERTIFICATE OF CORRECTION.

Patent No. 1,826, 955.

SAMUEL RUBEN.

Granted October 13, 1931, to

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,line 105, for "for" read from; and that the said Letters Patent shouldbe read with this correction therein that the same may conform to therecord of the case .in the Patent Office.

Signed and sealed this 9th day of February, A. D. 1932.

M. J. Moore,

(Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 1,826,955. Granted October 13, 1931, to

SAMUEL RUBEN.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,line 105, for "for" read from; and that the said Letters Patent shouldbe read with this correction therein that the same may conform to therecord of the case ,in the Patent Office.

Signed and sealed this 9th day of February, A. D. 1932.

M. J. Moore, (Seal) Acting Commissioner of Patents.

